The upper gastrointestinal tract of pet birds has several unique features.
- Diverticulum. After being swallowed, food moves into a diverticulum of the esophagus called the crop. The function of the crop is to moisten, soften and store food.
- Proventriculus. Food then moves from the crop into the first stomach, called the proventriculus. The proventriculus contains glands that secrete enzymes and acid to begin the chemical digestion of the ingested food.
- Ventriculus. Once these chemicals have been added, the food then moves into the second stomach, the ventriculus. The ventriculus contains two opposing sets of muscles, which grind and macerate the food.
- Peristalsis. Movement of food from the crop to the proventriculus to the ventriculus is dependent on highly coordinated contractions called peristalsis.
Vomiting should be differentiated from regurgitation. Regurgitation can be a normal behavior in a healthy bird, whereas vomiting is always abnormal. Vomiting occurs when food from the proventriculus or ventriculus is forcefully expelled through the mouth. This food is digested or partially digested and has an acidic liquid. Food that is regurgitated originates from the crop and is undigested.
Vomiting can be differentiated from regurgitation by observing both the behavior of the bird, and the appearance of the expelled food. Birds that are regurgitating will consciously and vigorously bob their head, and then bring the softened, undigested food into the mouth. This food may then be re-ingested, or dropped from the mouth.
Regurgitation is normal behavior during nesting and courtship. Birds often regurgitate food from their crops to feed to their mate or to feed to their offspring while in the nest. Pet birds often attempt to feed regurgitated food to their owners, cage mates, toys or shiny objects such as mirrors or bells. If regurgitation is a behavior not caused by disease, your bird should always be directing the behavior towards someone or something. If he is regurgitating food in the absence of such stimulus, or regurgitating excessively, seek veterinary attention.
In contrast, birds that are vomiting will suddenly bring digested food containing an acidic liquid from the proventriculus or ventriculus into their mouth. They will then rapidly spit out the fluid, usually by flinging their head from side to side. Often, the vomitus will spray out onto the bird's head and around the cage. Sometimes, a bird vomits stomach contents into the crop, and then regurgitates vomitus. Nevertheless, as soon as the foul-tasting stomach contents enter the mouth, it is rapidly spit out. Vomiting, unlike regurgitation, is not directed toward an object, and the bird does not re-ingest it.
Vomiting is always abnormal, and your veterinarian should be consulted. Birds that are vomiting and have other symptoms, such as diarrhea, lack of appetite or lethargy require immediate attention.
There are many causes of vomiting in birds. Vomiting can be caused by diseases of the digestive tract or can occur due to toxicities, disease of the nervous system or metabolic diseases. There are many contagious diseases that cause vomiting, so it is important to inform your veterinarian of any potential contact - direct or indirect - with other birds. Possible causes of vomiting in birds include:
- Obstruction. Ingested foreign objects may block the intestinal tract. Psittacine birds have powerful beaks, and a strong instinct to chew. Objects that commonly obstruct the intestinal tract include string toys, bark or wood shavings, and pieces of rubber toys.
- Toxins. Heavy metals, plants and cigarettes are commonly ingested. Most plants and cigarettes cause vomiting by irritating the intestinal tract. Heavy metal toxicity, caused by ingestion of objects containing lead or zinc, is one of the most common diseases seen in pet birds. Not all birds with heavy metal toxicosis vomit, and most have other symptoms, especially neurologic signs.
- Bacterial infection. Bacterial infections may come from other birds, from an overgrowth of dangerous bacteria on dirty food or water bowls, or spoiled foods. Often, small amounts of potentially dangerous bacteria live in the intestinal tract without causing harm. This population of bacteria can overgrow and cause disease if the bird's immune system is not functioning properly, as may occur during times of stress. An overgrowth of harmful bacteria may also occur when antibiotics are used improperly.
- Viral infection. Several different avian viruses may cause vomiting. In most cases, vomiting will be only one of several symptoms. Viruses can be transmitted by direct exposure to another bird, shared food or water dishes, or on your hands or clothing, depending on the type of virus.
- Yeast infection. Candida is a type of yeast that normally lives in small quantities in the intestinal tract. Stress or antibiotic use can also cause an overgrowth of Candida, leading to vomiting.
- Parasites. Trichomonas is a common cause of vomiting in small psittacine birds, especially budgerigars. Other intestinal parasites such as Giardia, heximita, coccida, roundworms and tapeworms, may occasionally be a cause.
- Antibiotics. Some antibiotics and antifungal medications may temporarily cause vomiting. Usually, this will stop once administration of the medication is discontinued.
- Cancer. Papillomas (wart-like structures) or cancer may occur anywhere along the gastrointestinal tract.
- Metabolic disorders. Liver disease, diabetes mellitus, renal disease can all result in vomiting.
- Neurologic disorders. Vomiting may be triggered by infection or inflammation of the brain, or by motion sickness.
- Dietary. Diet changes, eating spoiled food, dietary intolerance can all cause vomiting.
Vomiting is the forceful expulsion of the stomach contents through the mouth. The vomiting reflex may be triggered by irritation of receptors in the gastrointestinal tract or the brain. Birds that are vomiting are expelling food from the proventriculus, which is the glandular or first stomach. This food is usually digested or partially digested, and may contain an acidic liquid. Vomiting in birds is always abnormal.
At times, birds may regurgitate, that is, expel food originating from the crop through the mouth. But this is mainly undigested food. Regurgitation may be caused by disease processes, or may be a normal behavior.
Vomiting can be distinguished from regurgitation by observing the bird. Birds that are regurgitating will consciously and vigorously bob their head, and then bring softened, undigested food into the mouth. This food may then be re-ingested, or dropped from the mouth.
Birds that are vomiting will suddenly bring digested food containing an acidic liquid from the proventriculus into their mouth. They will then rapidly spit out the fluid, usually by flinging their head from side to side. Often, the vomitus will spray out onto the bird's head and around the cage. Sometimes a bird will vomit stomach contents into the crop, and then regurgitate vomitus. Nevertheless, as soon as the foul-tasting stomach contents enter the mouth, the bird rapidly spits them out.
- Bacterial infections
- Intestinal yeast infections
- Viral infections
- Intestinal obstruction
- Metabolic diseases, such as liver or kidney disease
Your veterinarian will recommend specific diagnostic tests depending on how long your bird has been vomiting, and whether any other symptoms, such as anorexia or listlessness, are present.
If your bird is regurgitating and the act is directed towards a person, animal or object, it may be a normal behavior. However, if your bird is not directing the regurgitation towards anything, or is shaking his head to spit out the vomitus, medical attention is needed.
What to Watch For
- Ruffled feathers
- Tucking the head under the wing
- Loss of appetite
- Blood in the stool, which appears as dark, green-black tarry stool
- Lack of feces in the dropping
Your veterinarian will recommend specific diagnostic tests depending on the severity of the vomiting or if other symptoms are present. In almost every case, birds that are vomiting require extensive diagnostic testing.
A complete history is extremely helpful in reaching a diagnosis. Be prepared to tell your veterinarian when the vomiting began, the consistency of the vomitus, and whether it contains digested or undigested food. Additionally, tell your veterinarian the type of diet your bird is on, describe his chewing habits and note any potential exposure to other birds.
Diagnostic testing your veterinarian may perform include:
- A thorough physical examination
- A complete blood count (CBC) and serum biochemistry panel
- Sampling the crop and/or feces for bacterial culture and cytology
- Radiography (X-Rays) to look for evidence of intestinal disease
- Endoscopy to view the intestinal tract or body cavity
Treatment for vomiting may include any of the following:
- Hospitalization for fluids and injectable medications
- Antibiotics or antifungal medications
- Surgery or endoscopy to relieve intestinal obstructions
- Medications to protect the intestinal tract or alter the motility of the intestinal tract
If your bird is vomiting, veterinary attention is needed. Immediate attention is necessary if any other symptoms are present in addition to vomiting, or if your bird is unable to keep any food down. In the meantime, keep your bird in a warm environment if his feathers appear fluffed up. If possible, bring the cage to the veterinarian's office with the bird, along with any toys he may have chewed.
After seeing your veterinarian, be sure to give all medication as directed, for as long as directed, even after the symptoms appear to be gone. Watch for a change in the droppings, and report any changes to your veterinarian. If improvement is not seen, report this to your veterinarian.
A thorough history is extremely important in the diagnosis of vomiting. Be able to answer the following questions:
- When did the problem begin?
- How often does the bird vomit?
- Has there been an increase (or decrease) in the frequency?
- What does the vomit look like?
- Is the vomit digested or undigested food?
- Has the diet changed?
- Are fresh foods, such as fruits and vegetables fed regularly?
- Is the bird still eating a normal amount of food?
- What are the bird's chewing habits?
- Does he have access to metal objects or plants?
- Does the bird chew apart wood, rubber or string toys?
- Are any other symptoms, such as lethargy or diarrhea, present?
- Has the bird been exposed to other birds?
- How often is the cage, especially the food and water dishes, cleaned, and how are they cleaned?
Your veterinarian will recommend specific diagnostic tests depending on how severe the vomiting is, if other symptoms are present, or how long the problem has been going on. In most cases, extensive diagnostic testing is required. Any combination of the following may be recommended:
- A thorough physical examination.
- Sampling the crop, feces or cloaca for bacterial culture and cytology (looking at cell types for evidence of infection or inflammation).
- Sampling of the crop or feces to look for intestinal parasites.
- A complete blood count (CBC) to determine the number of circulating white blood cells. This may be helpful in distinguishing between infectious and non-infectious causes of vomiting. The number of red blood cells may be diminished if bleeding in the intestinal tract is present.
- A serum biochemistry panel is needed to look for evidence of metabolic problems, such as diseases of the liver, kidney or pancreas.
- Plasma protein electrophoresis looks at the types of proteins present in the circulation. For example, birds with chronic diseases, especially infectious or inflammatory diseases, will produce antibodies, and an increase in one class of proteins (gammaglobulins) will occur. Birds with liver disease or severe intestinal disease usually have low concentrations of another class of protein (albumin).
- Blood tests or other samples for Chlamydiosis (Psittacosis).
- Blood tests that measure the concentration of heavy metals, such as lead or zinc in circulation.
- Radiography (X-Rays) to look for evidence of intestinal disease, foreign bodies, and the size and density of the liver, kidneys or other organs.
- Contrast radiographs, such a barium studies, to look for tumors or foreign bodies, ulcerations or thickening of the lining of the intestinal tract. This test will also determine how quickly ingested material is moved through the intestinal tract.
- Fluoroscopy (a video or moving X ray) to determine if the coordination of peristaltic waves is normal. It is useful in the diagnosis of toxicity (lead or zinc), foreign bodies or viral diseases (proventricular dilatation disease).
- Abdominal ultrasound to visualize the intestinal tract for evidence intestinal wall thickening, gastrointestinal masses and foreign bodies. This procedure is only possible in birds with enlargement of the liver or fluid in the abdomen and is performed by a specialist.
- Endoscopy to view the intestinal tract or body cavity directly and to collect samples for biopsy or culture. Some foreign bodies may be removed with an endoscope. A specialist usually performs this test.
- Exploratory surgery (laparotomy) to observe and obtain segments of the intestinal tract for biopsy in order to determine the cause of vomiting.
Until a diagnosis is made, treatment of the symptoms might be necessary, especially if the problem is severe. The following treatments may be applicable to some, but not all birds that are vomiting. Theses treatments may reduce the severity of symptoms, or provide relief for your bird. However, nonspecific therapy is not a substitute for definite treatment of the underlying disease responsible for your bird's condition.